Fix devicestate protobuf / filesize allocation (#5835)

src/mesh/NodeDB.cpp

@@ -958,7 +958,7 @@ void NodeDB::loadFromDisk()
 #endif
 
     // static DeviceState scratch; We no longer read into a tempbuf because this structure is 15KB of valuable RAM
-    auto state = loadProto(prefFileName, sizeof(meshtastic_DeviceState) + MAX_NUM_NODES_FS * sizeof(meshtastic_NodeInfo),
+    auto state = loadProto(prefFileName, sizeof(meshtastic_DeviceState) + MAX_NUM_NODES_FS * meshtastic_NodeInfoLite_size,
                            sizeof(meshtastic_DeviceState), &meshtastic_DeviceState_msg, &devicestate);
 
     // See https://github.com/meshtastic/firmware/issues/4184#issuecomment-2269390786
@@ -1147,8 +1147,9 @@ bool NodeDB::saveDeviceStateToDisk()
 #endif
     // Note: if MAX_NUM_NODES=100 and meshtastic_NodeInfoLite_size=166, so will be approximately 17KB
     // Because so huge we _must_ not use fullAtomic, because the filesystem is probably too small to hold two copies of this
-    return saveProto(prefFileName, sizeof(devicestate) + numMeshNodes * meshtastic_NodeInfoLite_size, &meshtastic_DeviceState_msg,
-                     &devicestate, false);
+    size_t deviceStateSize;
+    pb_get_encoded_size(&deviceStateSize, meshtastic_DeviceState_fields, &devicestate);
+    return saveProto(prefFileName, deviceStateSize, &meshtastic_DeviceState_msg, &devicestate, false);
 }
 
 bool NodeDB::saveToDiskNoRetry(int saveWhat)